The internal cleaning of cans calls for a great deal of design-related and experimental expenditure, as exemplified by JP 2002096807 A. As is the case here, the internal cleaning process is performed by spraying-on a cleaning fluid within an aseptic atmosphere.
In addition, DE 296 09 831 U1 is concerned with the insertion, in portions, of fluids into cans. The cans are moved in a circle using a rotor, whereby the cans stand upright on their base. How and whether the cans are subjected to prior internal cleaning remains unclear.
Furthermore, the overhead handling of bottles is basically known about, as is described in DE 42 29 580 A1. In this case, the bottles are rinsed, that is to say, the inside of the bottles is washed out with a cleaning fluid. Special bottle grippers are used for this purpose, and the mouth of the bottle is treated with a sterilization medium.
DE 10 2006 044 904 A1 operates in a similar manner, whereby a spraying unit enters the inside of the bottle, preferably up as far as the base. Special devices are also required in this case to hold the bottle in the desired overhead position.
Such procedures do not have any application for the cleaning of the inside of cans with an opening. This is because, in particular, drink-cans are, these days, predominantly made from very thin steel plate in order to keep the costs and the use of materials down to the lowest possible level. As a consequence, the basic problem that arises with mechanical manipulation of cans is that their surfaces are susceptible to damage and that, in the worst case, they can be crushed. As a result, their subsequent sale becomes impossible.
For this reason, in normal practice, the process of cleaning the inside of cans with openings usually involves the use of linear gravity rinsers. These devices generally have a spiral guide rail for the cans. The cans are then conveyed individually by the effect of gravity along the guide rail and are subjected to a 180° turn so that, at the end of the guide rail conveying process, they stand head downwards in the overhead position.
The cans in the overhead position are then treated with a cleaning medium. The cleaning medium is dispensed by a fixed nozzle assembly onto the cans or into their interior. The cans are treated from the bottom upwards using this nozzle assembly, which has nozzles set at intervals extending lengthwise from the respective opening.
As a result of the spacing of the nozzles from the opening, the jet of the cleaning medium is constantly interrupted and is, for example, reflected on the walls of the cans. Due to this, a relatively large amount of cleaning medium is needed, much of which does not achieve any targeted internal cleaning and is therefore wasted. This results in increased costs that have to be taken into account.